Two moms whose sons died after being exposed to a toxic chemical common in paint thinners sued the Environmental Protection Agency this week, saying the agency has dragged its feet to ban products that are harmful to human health.

Lauren Atkins and Wendy Hartley filed the suit on Monday alongside the Vermont Interest Research Group and Safer Chemicals Healthy Families over the chemical methylene chloride, which is used in some paint strippers, commercial adhesives and cleaning products. Atkins’ son Joshua died after inhaling fumes from the chemical while refinishing a bike part in a bathroom. Hartley’s son Kevin died after similar exposure while using paint stripper on a bathtub.

The chemical can easily be obtained by everyday consumers but has been linked to more than 50 reported deaths, according to the suit. The Centers for Disease Control and Prevention notes exposure can result in dizziness, nausea and numbness in extremities after limited exposure, and unconsciousness or death at higher rates.

Under former President Barack Obama, the EPA first proposed banning methylene chloride in consumer products. Former agency administrator Scott Pruitt, who was appointed by President Donald Trump, pledged last May to finalize the ban after meeting with Hartley, but after Pruitt was forced to resign months later, the proposal never moved forward.

“10 months after Mr. Pruitt’s explicit vows to finalize the proposed ban, no rule has been issued and MC paint removers continue to place Americans at risk of lethal health effects,” the suit says.

Many of America’s largest retailers have already taken action against the chemical, including Lowe’s, Home Depot, Amazon and Walmart, citing the dangers of the product.

Bob Sussman, an attorney representing Atkins and Hartley, told BuzzFeed news that the longer the chemical remains on the market, the more danger it poses to Americans.

“It’s a very dangerous chemical, and since the EPA rule was proposed in 2017, there have been at least four deaths and there will probably be more deaths unless the EPA acts to get it off the market,” Sussman, who worked for the EPA under Presidents Bill Clinton and Obama, told BuzzFeed. “It’s disturbing that EPA is not taking action here and that even now is hedging its bets.”

The Washington Post reported that since the Obama administration first proposed banning the product, four people including Kevin Hartley have died of exposure to methylene chloride. The newspaper also reported last week that the EPA has sent out proposals to continue the use of the chemical in commercial applications while banning it publicly, a plan that prompted immediate ire from some lawmakers.

“Despite explicit assurances provided to my office that EPA would finalize a ban that protected both consumer and commercial users from this dangerous chemical, the Trump EPA appears to have failed to live up to those assurances,” Sen. Thomas R. Carper (D-Del.) told the Post. “I will do everything in my power to ensure that the final rule takes all needed steps to ban a chemical so dangerous that it has killed dozens of Americans, including trained professionals who were taking precautions on the job.”